Open AccessPiezoelectric and acoustic behavior of polypropylene piezoelectret films
Author(s) -
Xinwu Zhang,
Xiaoqing Zhang
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.167702
Subject(s) - materials science , piezoelectricity , composite material , piezoelectric coefficient , modulus , polypropylene , transverse plane , elastic modulus , young's modulus , ultrasonic sensor , acoustics , structural engineering , engineering , physics
Piezoelectrets are made from cellular polypropylene(pp)foam sheets by using a pressed-gas expansion followed by corona charging process. The elastic modulus, piezoelectricity and the acoustic response of such fabricated films are investigated. The results show that the Youngs modulus in the thickness direction is more than two orders of magnitude higher than those in the transverse directions. The d33 coefficient remains linear in an applied pressure range from 15 to 35 kPa. As measuring frequency increases from 2 to 300 Hz, d33 coefficient decreases to 81%, which is probably associated with the enhancement of elastic modulus of the film with pressure increasing. In a range from 100 Hz to 100 kHz, the PP piezoelectric films exhibit flat frequency response curves. The open circuit voltage sensitivity and d33 coefficient at 1 kHz are 0.84 mV/Pa and 164 pC/N, respectively.